Water recharge program expected to surpass goal
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Idaho’s fledgling groundwater recharge program, aided by better than average snowpacks and predicted surplus flows, could exceed its goal this year.
The long-term goal is to recharge the Eastern Snake Plain Aquifer by 250,000 acre feet annually, a goal that’s yet to be met since the program began in 2009.
In fact, last November, the Idaho Water Resource Board set a recharge target of 108,000 acre feet for the 2016 to 2017 recharge season.
A winter of heavy snow and early runoff later, that initial goal already has been surpassed by double. As of April 7, the total acre feet of recharged water was 217,607.
It could go much higher. The agency’s recharge project manager, Wesley Hipke, told the Henry’s Fork Watershed Council on Tuesday that recharge could get beyond the 300,000 acre-feet level depending on how weather impacts snowpack runoff rates and on the amount of spring rain.
Groundwater recharge is not new to the region, but it has been given new emphasis by state and private water managers in recent decades due to documented declines in the aquifer levels.
Since farming began in the upper valley, incidental recharge has occurred. Water used in surface irrigation by any method seeps into the ground, recharging the vast aquifer beneath. According to Rob Van Kirk, a scientist who works for the Henry’s Fork Foundation, studies show 50 to 70 percent of surface water goes back into the Henry’s Fork eventually. Groundwater seepage accounts for 40 to 70 percent of groundwater recharge.
Artificial, managed recharge is a new focus, and it’s being accomplished both by the state and by private enterprise. The difference between the two is that the state’s aim in its recharge program is to refill the depleted aquifer, while the aims of private companies such as RDC, Recharge Development Co., are to create aquifer recharge units. The units, equal to 1 acre foot of water, can be bought and sold and can be used to augment water supply when an irrigator’s water rights end.
According to the water board, the volume of water in the Eastern Snake Plain Aquifer has been declining by about 200,000 acre feet per year since the early 1950s. The goal to recharge the aquifer by 250,000 acre feet per year aims to replenish that volume and augment it to bring it closer to historic levels. The purpose of the recharge program is to restore the aquifer from being over-drafted by groundwater users.
There is a catch. The only water available for the state’s recharge program is water that’s not already claimed through water rights and that can be conveyed to the recharge sites.
Recharge is occurring at five sites in the Upper Snake region and four sites in the Mid-Snake region in the Magic Valley area, according to the board.
The agency works with canal companies and irrigation districts to use their canals to send water into the ESPA.
A plentiful water year helps. And so does cooler, wetter spring weather. Recharge is allowed, in general, only in the irrigation offseason. When farmers begin to irrigate their fields in eastern Idaho and southern Idaho, recharge flows get turned off. But this year the weather has been so cool and wet that a few more weeks of recharge might happen before irrigation begins in earnest, allowing the board to reach a goal it hadn’t anticipated to hit until 2024.
With possibilities high that the long-term recharge goal may be hit this spring, interest has been high in the program. State Water Board members, for example, were in eastern Idaho on Monday to tour recharge program sites.
And the state recharge program manager was one of several speakers to address the HF Watershed Council Tuesday in a meeting totally devoted to groundwater recharge.
What’s ahead for the program in Idaho? Right now the focus is on improving and building infrastructure that will improve the state’s ability to capture more surplus water for recharge purposes.
At the Egin Lakes recharge sit, for example, a new canal has been built to carry recharge water farther into ponds in the sandy desert.
The state also is working on plans to better use infrastructure to capture water available for recharge.
Private recharge efforts also are focused on establishing better ways and places to capture the water available for recharge, though it’s more difficult for those efforts since their recharge sites can’t rely on public lands.
“The state is fortunate to have water,” RCD executive Dave Tuthill told the Watershed Council. “It’s a headwater state. The opportunity for private recharge is huge, also the opportunity for partnerships.”